In recent years, for a display part for a device displaying a video and an image, a liquid crystal display panel of an active matrix type using a switching element such as a TFT (thin film transistor) has widely been used. In such a display panel, for example, when performance of displaying moving videos is highly valued, there is a method for driving the device by doubling a frame frequency with a technique which is called as an FRC (Frame Rate Conversion). However, in a case where the frame frequency is doubled without changing the number of lines for one screen, the scanning time for one line is reduced to half. This requires improvement in the charging capacity of a TFT and speed up of a driving circuit for writing data in a display pixel (hereinafter, simply referred to as a pixel).
For example, Japanese Patent Application Laid-Open No. H2-296286 1 describes a substrate for a liquid crystal display in which drain wirings of TFTs (bus line of a data signal) applying a video signal (data signal) to pixel electrodes of pixels in each column are separately arranged for odd-numbered pixels and even-numbered pixels in each column in the vertical direction of a display screen, and a gate wiring of TFTs is arranged commonly for an odd-numbered scanning line and an even-numbered scanning line adjacent to each other in the horizontal direction of the display screen. Compared to a case where an odd-numbered scanning line and an even-numbered scanning line adjacent to each other are separately scanned, the structure allows the doubled scanning time per line and the halved scanning time per line due to the doubled frame frequency to cancel each other out.
In a liquid crystal display device of an active matrix type, a plurality of TFTs are connected to a drain wiring in the vertical direction of a display screen. Generally, only one TFT becomes active at the same time among the TFTs, and the remaining TFTs are inactive. Therefore, a problem may be caused by leakage of a data signal to a pixel electrode from an inactive TFT due to a parasitic capacitance between the drain and the source.
For example, Japanese Patent Application Laid-Open No. 2003-140625 describes a phenomenon as a problem that, when a white or a black box pattern (the circumference of a box region in the middle is a gray back region) is displayed in the middle of a display area, one of the gray back regions in the upper part and the lower part of the screen in the box region is displayed brighter and the other is displayed darker (hereinafter, referred to as shadowing).
To address this problem, according to a liquid crystal display device described in Japanese Patent Application Laid-Open No. 2003-140625, a different drain wiring is provided to TFTs in each column for capacitive coupling, and a compensation signal is supplied to the different drain wiring, thereby solving the problem. It seems that the problem of shadowing may be avoided by applying this technique together with the technique disclosed in Japanese Patent Application Laid-Open No. 112-296286 for displaying a three-dimensional image.